Mail.dll uses 4 different collections to store mail attachments: NonVisuals - real mail attachments, Visuals - visual elements (usually HTML images), Alternatives - alternative views of the root element other than text, html, rtf (e.g. iCal appointment), Attachments - all attachments (includes Visuals, NonVisuals and Alternatives). You can also use Appointments and VCards collections to access already processed ical appointments and business cards.